[Gnuplot-info] Coloring multi-column plot by column number

[t.sefzick <t.s...@gm...>]

Hi,

you could specify the linecolor as ARGBvalue by adding the "linecolor"
option to your plot command:

plot for [i=2:N] "input.dat" u 1:i with lines title "" linewidth 2 \
  linecolor rgb ((255-i) << 16) + ((255-i) << 8) + 255

starting from (nearly) white and ending with dark blue.
Works, if N is around 250 but below 255, otherwise you have
to add a scaling factor to the color computation.

Thomas

On Tue, Feb 18, 2020 at 11:13:16AM +0530, Debostuti Ghoshdastidar wrote:
> Hi
>
> I have a data set (input.dat) which looks as below:
>
> #C1     C2    C3 ...   C250
> 1          -2.1    -1.9...  -1.1
> 2
> .
> .
> .
> 10       -0.9    1.3        1.7
>
> My intention was that points 1 to 10 will be joined in each column to form
> each plot, and therefore I'll have a 249-line plot. This I am able to
> achieve by the following:
>
> N = system("awk 'NR==1{print NF}' input.dat")
> plot for [i=2:N] "input.dat" u 1:i with lines title "" linewidth 2
>
> Using this I obtain a plot where each line is plotted with a different
> color. I want the plots to be colored by a defined palette where the range
> is the column number itself, i.e., C2 will be the lightest blue and C250
> the darkest blue, since the columns are arranged based on a factor.
>
> Appreciate any help in this regard.
>
> Thank you
>
>
> --
> Debostuti Ghosh Dastidar
> DST SERB National Post-Doctoral Fellow
> Molecular Biophysics Unit
> Indian Institute of Science, Bangalore